February 1, 2008

SDSU BioScience Center to Study Link Between Periodontitis and Atherosclerotic Heart Disease

(San Diego Dentistry Article)

By Roberta Gottlieb, M.D.

The SDSU BioScience Center was established to study the links between infection, inflammation, and cardiovascular disease. One of the most important concerns is the periodontitis-atherosclerosis connection, which is well-recognized in the dental community. Numerous epidemiologic studies have reported an association, with a relative risk ratio of about 1.4. However, because there has not been a clear demonstration of causality, the American Heart Association does not list periodontal disease as a risk factor for atherosclerosis, and most cardiologists and internists pay little attention to oral health.


Atherosclerosis, or hardening of the arteries, is responsible for coronary artery disease, stroke, and peripheral vascular disease, which together represent the leading cause of death in the U.S. Approximately eight million Americans suffer from atherosclerosis, and the incidence and mortality from atherosclerosis is much higher among the disadvantaged. This same segment of society also has limited access to dental care and suffers from a higher incidence of periodontal disease, approaching 50% in some subgroups. The risk of periodontal disease is greatly increased in patients with diabetes, who also suffer from more severe cardiovascular disease.


The earliest and most sensitive predictor of atherosclerosis is a measure of vascular function called flow-mediated dilation. In men with established atherosclerotic disease, the presence of periodontal disease was associated with greater endothelial dysfunction, which improved after aggressive treatment of the periodontal disease. The major open question is whether treating periodontal disease early can delay or even prevent the development of atherosclerosis.


The SDSU BioScience Center proposes to address this question by studying periodontal disease and vascular dysfunction in disadvantaged Hispanic teens and young Native American. We have assembled a team of investigators including dentists, cardiologists, microbiologists, and epidemiologists. We will identify children and young adults with periodontal disease (and age-matched controls), and will evaluate them for early signs of atherosclerosis. After treating their periodontal disease we will reevaluate their vascular function. A second exciting aspect of this study is the detailed microbiological study planned. Using a new and powerful DNA sequencing technology, we will survey all microorganisms present in the mouths of patients with and without periodontal disease. This is coupled to bioinformatics technology which will allow us to associate bacterial species or complex bacterial populations with periodontal disease, atherosclerosis, or other conditions. We will also characterize the bacterial populations after periodontal treatment.


The study will be carried out in conjunction with Dorothy Zirkle, Director of Community School Programs for Price Charities, and Dr. Daniel Calac, Medical Director, and Dr. Carrie Lambert, Dental Director, both of the Indian Health Council located in Pauma Valley. We have assembled an outstanding team of investigators, including Dr. Anthony Demaria and Dr. Wendy Austin of UCSD Cardiology, microbiologist Dr. Scott Kelley and Lena van der Stap of SDSU Biology and Computation Sciences, Dr. Suzanne Lindsay and Dr. Stephanie Brodine of SDSU Graduate School of Public Health, and Dr. Jack Luomanen, DMD, of Community Dental Health Consultants. Dr. Nadia Hermiz of Calbiotech, Inc., will measure serum markers of inflammation that are known to accelerate atherosclerosis, including TNF-alpha, interleukin-6, and C-reactive protein. The study, once we have obtained the necessary funding, will take one to two years to complete. We hope to be able to demonstrate that periodontal disease is a treatable contributing factor in the development of atherosclerotic heart disease. This study will be important to establishing new heart disease prevention guidelines for the American Heart Association and the American Academy of Pediatrics.


The BioScience Center is committed to responding to the microbial basis of heart disease through research, public health, and technology development. We currently have four faculty members with plans to recruit 8 more in the coming years, and are in the early stages of fundraising to complete the construction of two remaining floors. Other research programs in the BioScience Center focus on ischemic heart disease, Chagas disease, viral cardiomyopathy, and obesity.